The provision of a mechanical seal assembly for preventing leakage along a rotary shaft extending into or through a housing, such as a pump housing, has involved the utilization of double and tandem seals, each including a pair of complemental relatively rotatable seal rings respectively carried by the housing and the shaft through suitable mounting means. Where high temperature fluids are encountered, the seal assembly, and more particularly the seal rings may be cooled by a coolant fluid circulated through the seal chamber and through a surrounding heat exchanger. To assist in cooling, the heat exchanger may be exposed externally of the housing or may be subjected to air flow induced by a fan rotatable with the shaft.
One form of heat exchanger is shown and described in U.S. Pat. No. 3,884,482, granted May 20, 1975 and a division thereof U.S. Pat. No. 3,941,395, granted Mar. 2, 1976.
In the heat exchanger shown and described in the aforesaid patents, coolant fluid is circulated by an axial flow impeller associated with the shaft and a housing and a flow path for the coolant fluid is provided in between the housing and a jacket having cooling fins. Cooling air is impelled along the fins by an air pump associated with the shaft.